A nyers juh- és kecsketej minőségét befolyásoló főbb tényezők

Abstract

SUMMARY Based on large number of publications in scientific literature, the author provide information on the factors affecting the quality of raw sheep and goat milk. She presents the effect of the variety within species, the impact of stage of lacta tion and seasons, the influence of milking and changes in somatic cell count in milk composition. In sheep milk the amount of milk fat, milk protein and casein in the final stage of the lactation rises compared to the first stage. In goat milk the concentration of milk fat decreases in the middle stage of lactation compared to the first stage and it increases in the final stage and the amount of milk protein and casein constantly increases during the lactation. High milk yield is usually combined with a long lactation period, normally 8-10 months, but the dairy sheep maintain lactation for 2 years without more calving. A high somatic cell count milk have a higher proteolytic activity, and they contain larger quantities of fat and casein and lower concentration of whey proteins, especially serum albumin and immunoglobulin. The proteolytic enzymes in the somatic cells attack the αs2- and β-casein. Just like the goats, the sheep also respond to changes in the environment, they have developed a genetic multiplication pace that follows the seasons change and the better food endowments. If the lacta tion period begins before the spring or the rainy season, lactation period will be longer because of the better feed. There is 80-90% correspondence between the udder size and the milk yield, and the milk yield depends on the surface size of alveoli, too. Increasing the number of milking ordinarily increases the amount of the expressed milk, but in this case there are significant differences between individual animals.